Process of making calcium carbid.



PATBNTED MAY 17, 1904.

A. H. oow Es. PROCESS OF MAKING CALCIUM 0ARBID.-

APPLI OATION FILED JUNE 28, 1902.

N0 MODEL.

Witness e5 YM: Moms Pinks co, wow-mac, msumown. o. c,

Patented May 17, 1904.

UNITED STATES PATENT OFFICE.

ALFRED OOVVL'ES,OF CLEVELAND, OHIO.

3 PROCESS OF MAKING CALCIUM CARBID.

SPECIFICATION forming part of Letters Patent No. 760,312, dated. May 17, 1904.

Application filed June 28, 1902.; s al N... 113,639. (No specimens.)

To all whom, it. may concern:

Be it known that LALFRED H. CowLns, a i citizen of the United States, residing at Cleveland, in the county of Ouyahoga and. State of Ohio, have invented certain new and useful Improvements in Processes of Making CalciumCarbid, of which the following is a specification. 7 I This process is intended forthe continuous production of calcium carbid and involves the use as ameans for heating the charge of raw p materials of a resistance-conductor which is raised to ahigh temperature by the passage of an electric current through it. The, process further involves, the use. ofa suflicient tern.- peratureto melt the carbid ormaintain, it in a molten condition andthe removal of the carbid from the furnace through a tap-hole or other suitable outlet, fresh nnjate 'ials. being supplied. as required-to replace those converted into carbid. The resistance-conductor may be a, carbon rod or core having suitable terminal connections to the source of electric current. The mixture of lime and carbon is then packed around the core and raised to the necessary temperature by the heat radiated from the incandescent core. It is desirable, however, to use as the resistance-conductor the mixture of lime and carbon which constitutes the furnacecharge. The charge in thiscase may be one containing large pieces of carbon which lie in contact with each other at various points, and thereby afford direct paths for the flow of current, the lime being distributed in the interstices between the pieces of coke. If the normal charge, however, consists of a not sufficiently conducting mixture of coke and lime, the furnace may first be'put into operation by use of a conducting-core or by otherwise providing initial paths for the flow of current. The current passing in the first instance soon raises the temperature of that portion of the mixture between the electrodes to a point which will enable it to act as a resistance-conductor. In normal Working condition the body of material between the electrodes may consist partly of incandescent but unreduced material and partly of molten or semimolten carbid. The temperature maintained in the furnace is preferably sufficient to cause a pool of the molten carbid to collect adjacent to the tap-hole, the

carbid being tapped out either intermittently tor, material undergoing reduction, and molten carbid may be held in a cavity made within a pile of the mixture of lime and coke conshapedwaterrjacketed top 6 is supported upon 5 the casing-2, being insulated therefromby a This tophas double walls,

ring 7, of asbestos. preferably of sheet-iron, and water inletand' outlet pipes 8 9. leadingto the space between the walls. Feeding-hoppers 10, here shown as three in number, are arranged to discharge raw material through the top into the furnace.

- A pipe 11 serves to deliver waste gases from the furnace.

ing supplied to it through the bottom of the casing 2 and a terminal 12, bolted to the casing. The other electrode 13 is made of carbon, suspended vertically within the furnace by a metal terminal 14., having an upwardlyextending stem 15. A sheet-metal casing 16 is supported on the top of the furnace, being insulated therefrom by an asbestos ring 17. The stem 15 of the upper electrode passes adjustably through a stufling-box 18' at the upper end of this casing. The electrodes are connected to a suitable source of current, preferably an alternating one.

In operation the charge of lime and coke is fed in through the hoppers until it fills the furnace to a height somewhat above the lower end of the upper electrode. That portion of the charge between the electrodes is then 100 A tap-hole 4, hav- The carbon hearth serves as oneof the electrodes of, the furnace, current be-- brought to incandescence in any well-known manner and maintained at a temperature sufficient to effect conversion of the charge into carbid. Molten carbid accumulates on the hearth and is removed through the tap-hole, and further portions of the charge are fed in through the hoppers. the process thus being a continuous one. If the normal charge is a not sufficiently conducting mixture of lime and coke, it soon becomes heated as it descends into the furnace by the heat thrown off from the resistance-conductor or that portion of the charge between the electrodes and by the waste gases rising from the Zone of reduction to a temperature which will enable it to act as a resistance-conductor when it descends into the paths of current flow.

While the resistance-conductor employed is preferably the charge itself or the resulting carbid, a permanent resistance-conductor, such as a carbon rod, may be inserted between the electrodes 1 and 13, as indicated by dotted lines.

The word tapping as used in the claims is intended to cover the removal of molten carbid through a tap-hole or by any suitable means. The term body of superheated molten carbid used in the claims is intended to mean a body of carbid which has not only been produced and melted by the heat from the resistance-conductor, but which has also been raised thereby to such a temperature that it will run through a suitably-located tap-hole without requiring further heat to be supplied to it to compensate for that lost by conduction and radiation. It is not practicable to tap molten calcium carbid from an electric furnace unless it is either superheated or more heat is supplied to it at the tap-hole, its temperature of fusion being so high and the heat losses during its transit to and through the'taphole being so great that it will otherwise become viscid or solid and clog the tap-hole.

I claim 1. The process of making calcium carbid, which consists in heating a resistance-c0nductor to incandescence by passing an electric current through it, subjecting carbid-forming materials placed around said conductor to the heat from said conductor and thereby producing a body of superheated molten carbid, and tapping out carbid and supplying fresh materials as required.

2. The process of making calcium carbid. which consists in heating a resistance-conductor of carbid-forming materials or carbid produced therefrom to incandescence by passing an electric current through it, subjecting carbid-forming materials placed around said eonduct-or to the heat from said conductor and thereby producing a body of superheated molten carbid, and tapping out carbid and supplying fresh materials as required.

3. The process of making calcium carbid, which consists in heating carbid-forming materials to a temperature sufficient to produce a body of superheated molten carbid by passing an electric current through said materials, or carbid produced therefrom, acting as a resistance-conductor, and tapping out carbid and supplying fresh materials as required.

4:. The process of making calcium carbid, which consists in maintaining a resistance-conductor of carbid in a superheated molten condition by passing an electric current through it, subjecting carbid-forming materials placed around said conductor to the heat from said conductor and thereby producing further amounts of superheated molten carbid, and. tapping out carbid and supplying fresh materials as required.

5. The process of making calcium carbid, which consists in heating a vertical resistanceconductor to incandescence by passing'an electric current through it, siibjecting carbidforming materials placed around said conductor to the heat from said conductor and thereby producing a body of superheated molten carbid, and tapping out carbid and supplying fresh materials as required.

6. The process of making calcium carbid, which consists in heating a vertical resistanceconductor of carbid-forming materials or carbid produced therefrom to incandescence by passing an electric current through it, subjecting carbid-forming materials placed around said conductor to the heat from said conductor and thereby producing a body of superheated molten carbid, and tapping out carbid and supplying fresh materials as required.

In testimony whereof I affix my signature in presence of two witnesses.

ALFRED H. COVLES.

WV'itn esses:

A. E. RoBINsoN, HORACE W. POWERS. 

